Volume of triangular prism base 10 m height 4 m length 2 m

Step by step

The question

Question: find the volume of a triangular prism with triangle base 10 m and height 4 m, and length 2 m.

1 Area of the base

A prism has the same shape all the way through.

Here it is a triangle.

The triangle is the base.

Careful: the prism lies on its side.

Its base is the triangle at the end, not the face it lies on.

The triangle is half of the box around it.

So its area is half of base times height: A = ½ × 10 × 4.

10 times 4 is 40.

That is the whole box.

Half of 40 means 40 divided by 2.

That is 20.

So the base is A = 20 m².

2 Base times length

The prism is that triangle, stacked up 2 m long.

So the volume is V = A × length.

Now put the numbers in: A = 20 and length = 2.

20 times 2 is 40.

We count cubes, so the unit is m³.

So the volume is 40 m³.

Let's look back.

First: area of the base.

Last: base times length.